1. Field of the Invention
The invention broadly pertains to means for positioning and securing reinforcing steel in a variety of concrete structural members, such as reinforced concrete columns and beams.
More specifically, the invention is directed to a unique support member for reinforcing steel bars whereby the steel reinforcement is accurately located within a concrete structural member and is positively restrained from undesirable axial or rotational movement during placement of the concrete.
A critical element of reinforced concrete design involves the accurate placement and support of the reinforcing steel bars in the concrete structural member. It is essential that the reinforcing steel be precisely located and supported the required distance inside the face of the concrete. Failure to maintain the reinforcing steel a sufficient distance inward of the face of the concrete results in detrimental oxidation of the steel reinforcement, thereby significantly compromising the integrity of the structural member and necessitating exceedingly costly and extensive restoration of the structure. The support member of the instant invention addresses and eradicates the normally prevalent problem of oxidation associated with reinforced concrete members by insuring accurate location of the steel reinforcement the optimum distance inside the face of the concrete.
The detrimental effects of oxidation can only be entirely prevented when the reinforcing steel is not only accurately positioned inside the concrete face, but when the reinforcing steel is also restrained from axial and rotational movement during placement of the concrete so as to prevent unwanted shifting of the steel from its required position. Moreover, the integrity of a concrete structural member is determined by how effectively the reinforcing steel bars are locked in position within the concrete form to prohibit shifting of the steel when the concrete is placed. The subject support member positively prevents undesirable movement of the reinforcing steel from design parameters and thereby enhances the design efficiency of architects and engineers for reinforced concrete structures. The attributes in design and placement of the reinforcing steel realized through utilization of the reinforcing steel support member of the present invention result in lower costs of construction and maintenance for reinforced concrete structures.
The foregoing objects are achieved with the present invention in the form of a support member for reinforcing steel, which support member lends itself for utilization in locating and positioning both horizontal and vertical reinforcing steel the required distance inward of the concrete form. The invention further contemplates the utilization of a second reinforcing steel placement member particularly adapted for positioning the horizontally disposed top and center steel reinforcement in structural members such as beams, slabs and the like. Moreover, the instant support member is advantageous for its heretofore unparalleled simplicity and economy and may be easily formed to accommodate various sizes of reinforcing steel and diverse spacing requirements.
2. Description of the Prior Art
It is known in the prior art to provide supports, or chairs, for reinforcing steel rods disposed horizontally in a concrete structural member. Supports of this general type are disclosed in U.S. Pat. No. 1,620,501; U.S. Pat. No. 1,659,795 and U.S. Pat. No. 3,881,833.
U.S. Pat. No. 1,620,501, issued Mar. 8, 1927 to Vogel, teaches a concrete reinforcing rod chair for supporting lower and upper reinforcing rods comprising a wire rod that is laterally bent to form an upper portion and two uprights with U-shaped loops providing seats for the rods.
U.S. Pat. No. 1,659,795, issued Feb. 21, 1928 to White, discloses a bar chair including two sections of wire which are bent and assembled to form a stable tripod having a pocket at the upper end for receipt of a reinforcing bar.
U.S. Pat. No. 3,881,833, issued May 6, 1975 to McMullen, teaches a wire frame structure for supporting dowels in pavement sections. The wire frame structure comprises a plurality of rod supporting elements which are characterized by upright legs and loops or hooks for receipt of the dowels.
It is also known in the prior art to support steel reinforcing bars, disposed transverse to each other, in a concrete member. Examples of this type of reinforcement supporting means are shown in U.S. Pat. No. 1,623,252; U.S. Pat. No. 1,651,946 and U.S. Pat. No. 4,388,791.
U.S. Pat. No. 1,623,252, issued on Apr. 5, 1927 to Konrad, discloses reinforcing means including a plurality of interconnected longitudinal and transverse bars.
U.S. Pat. No. 1,651,946, issued Dec. 6, 1927 to Burrell, is directed to a bar support comprising a spiral bight through which a reinforcing bar is adapted to be projected and a leg formed on each end of the bight. Each leg is provided with a pocket for projecting therethrough a transverse reinforcing rod.
U.S. Pat. No. 4,388,791, issued June 21, 1983 to Anderson, teaches a rebar tie comprising an elongated member having a curved mid-portion for seating on a vertical rebar, and a pair of parallel legs which clip onto horizontal rebars.
Furthermore, a locator for vertical reinforcing bars is shown in U.S. Pat. No. 4,190,999, issued on Mar. 4, 1980 to Hampton. Disclosed therein is a locator of ladder-like configuration and having circular rings for receiving vertical reinforcing bars.
The prior art fails to disclose a simple, unitary support member of the type disclosed by the subject invention which is capable of accurately positioning horizontal and/or vertical reinforcing steel in relation to a concrete form and effectively restraining said reinforcing steel from axial and rotational movement.